package com.czk.model.facade;

public class Screen {
    private Screen() {
    }
    public static final Screen screen = new Screen();

    public static Screen getInstance() {
        return screen;
    }

    public void up() {
        System.out.println("窗帘上升");
    }

    public void down() {
        System.out.println("窗帘下降");
    }
}
